The objective of the present study was to further develop and substantiate classification of chronic tonsillitis with due regard for etiology and pathogenesis of this disease. The author pays special attention to the fact that the toxico-allergic effect of focal infection of palatine tonsils (chronic tonsillitis, CT) is significantly more pronounced than that of focal infections of a different localization. The toxico-allergic manifestations of chronic tonsillitis are not infrequently realized through the associated non-specific infectious local and general complications and catalyze pathogenesis of the concomitant diseases. The classification developed taking into consideration etiology and pathogenesis of CT distinguishes two forms of chronic tonsillitis, viz. simple and toxico-allergic (TAF) CT, the latter being subdivided into two variants differing in the character of manifestations (TAF-1 and TAF-II). The clinical, morphological, and immunological characteristics of either form are described. It is emphasized that the most informative signs and symptoms of CT include the recurrence rate of tonsillitis in the medical history, purulent discharge from the tonsillar crypts apparent upon compression of their anterior surface with a spatula, and toxico-allergic reactions in combination with local signs and tonsillitis in the medical history. The therapeutic strategies for each forms of CT are specifies. The use of conservative therapy is recommended as the principal method for the treatment of the simple form, the strict compliance with the prescribed therapeutic modalities and repetition of the second therapeutic course within 3-4 months after the initial one being of primary importance. The treatment of TAF-1 should be started from conservative therapy the duration of which needs to be reduced in the absence of the marked desired effect bearing in mind the possibility of development of local and systemic complications. TAF-II requires urgent tonsillectomy because this condition is fraught with immediate severe complications.